Upcoming Freeform mermaid drama Siren has added Black Sails alum Sibongile Mlambo. The series will be premiering sometime in 2018.

Deadline is reporting that Black Sails alum Sibongile Mlambo has joined upcoming Freeform drama Siren as a series regular. She’ll be playing Donna, a mystifying and deceptively powerful mermaid.

From Dean White (The 100) and Eric Wald (View from the Top), with Emily Whitesell (Finding Carter) to showrun, Siren tells the story of Bristol Cove, a peaceful little coastal town purported to have been the home of mermaids long ago. However, when bright marine biologist Ben (Alex Roe) meets mysterious newcomer Ryn (Eline Powell), the validity of what was thought to simply be a legend brings about a vicious battle between man and sea.

In addition to her role on the Starz drama, Mlambo has appeared on the likes of Teen Wolf, Mad Dogs, and Strike Back. She joins a cast that includes Ian Verdun (Lucifer), Rena Owen (Once Were Warriors), and Fola Evans-Akingbola (Death in Paradise).

Siren is set to premiere in 2018 on Freeform. You can check out the first trailer here.